Đang chuẩn bị liên kết để tải về tài liệu:
Unit_3 : Computer capabilities and limitations

Like all machines, a computer needs to be directed and controlled in order to perform a task successfully. Until such time as a program is prepared and stored in the computer’s memory, the computer “knows” absolutely nothing, not even how to accept or reject data. Even the most sophisticated computer, no matter how capable it is, must be told what to do. Until the capabilities and the limitations of a computer are recognized, its usefulness cannot be thoroughly understood. | Unit 3 Computer capabilities and limitations Like all machines a computer needs to be directed and controlled in order to perform a task successfully. Until such time as a program is prepared and stored in the computer s memory the computer knows absolutely nothing not even how to accept or reject data. Even the most sophisticated computer no matter how capable it is must be told what to do. Until the capabilities and the limitations of a computer are recognized its usefulness cannot be thoroughly understood. In the first place it should be recognized that computers are capable of doing repetitive operations. A computer can perform similar operations thousands of times without becoming bored tired or even careless. Secondly computers can process information at extremely rapid rates. For example modern computers can solve certain classes of arithmetic problems millions of times faster than a skilled mathematician. Speeds for performing decision-making operations are comparable to those for arithmetic operations but input-output operations however involve mechanical motion and hence require more time. On a typical computer system cards are read at an average speed of 1000 cards per minutes and as many as 1000 lines can be printed at the same rate. Thirdly computers maybe programmed to calculate answers to whatever level of accuracy is specified by the programmer. In spite of newspaper headlines such as Computer Fails these machines are very accurate and reliable when the number of operations they can perform every second is considered. Because they are man-made machines they sometimes malfunction or break down and have to be repaired. However in most instances when the computer fails it is due to human error and is not the fault of the computer at all. In the fourth place general-purpose computers can be programmed to solve various types of problems because of their flexibility. One of the most important reasons why computers are so widely used today is that almost .